Household electric toaster

ABSTRACT

A low cost toaster having a metal body and plastic end panels. The end panels have cooling inlet vents near their lower ends and the top wall of the metal body has air outlet vents. Ambient air admitted through the inlet vents flows upwardly through the toaster and outwardly through the outlet vents to provide a cooling effect sufficient to allow the use of inexpensive plastic material for molding the end panels. The toaster has a bread lifter made entirely from a wire rod, a bread lifter extension made entirely from a wire rod, and a toast color cam made entirely from a single piece of sheet metal.

CROSS REFERENCE TO RELATED APPLICATION

This is a division of application Ser. No. 08/944,150, filed Oct. 6,1997, now U.S. Pat. No. 5,924,355.

FIELD OF THE INVENTION

This invention relates to a household electric toaster but aspects ofthis invention can be used in other heating appliances, particularlytoasters for commercial use.

BACKGROUND OF THE INVENTION

Household toasters commonly have a control chamber separated by avertical front frame plate from a toasting chamber. A bread carriageplate, termed a "bread lifter plate" herein, is slidably received on asupport post in the control chamber and carries a pair of breadsupports, termed "bread lifters" herein, that extend into and at leastpartially through the toasting chamber between heating elements therein.The lifter plate and accordingly the bread lifters arevertically-movable between a lowered position for holding bread or otherfood items in position to be toasted and a raised position forpermitting the bread or other food items to be placed on or removed fromthe bread lifters.

Some toasters have only one bread lifter and some have more than twobread lifters. For ease of discussion, this invention is disclosed foruse in a toaster configuration which has two bread lifters, suchpresently being the most common configuration. However, as will becomeapparent, aspects of this invention described below can be used in othertoaster configurations.

In many toasters, the bread supports are part of a vertically movablesupport carriage to which the bread supports are connected. Spring meansbiases the support carriage upwardly so that the bread supports arenormally in their upper, non-toasting position. The support carriage canbe lowered to the toasting position by manipulation of a control lever,termed a "lifter extension" herein, accessible from outside the housing.During a toasting cycle, a latch mechanism holds the support carriagewith its bread supports in their lowered, toasting position.User-adjustable electric means controls the toasting cycle times duringwhich the bread supports are latched in their lowered position in orderto toast the food items to the desired toast color.

A latch comprising a pivotally mounted armature or latch plate biasedaway from the face of the solenoid coil hooks over an upwardly-facingsurface on the bread carriage plate when the carriage plate is loweredto its toasting position. To terminate a toasting cycle, a solenoidswitch is closed, causing the solenoid to be energized, whereupon thelatch plate is pulled toward the solenoid coil and unhooked from thecarriage plate. The bread lifter spring returns the bread lifterassembly to its raised position during which time the bread lifter thatwas holding the power switch closed moves upwardly away from the powerswitch and the power switch opens.

In order to energize the solenoid coil at the end of the toasting cycle,a bimetal heat sensing assembly in the toasting chamber drives ahorizontally-movable switch operating shaft outwardly toward a movableswitch contact located in the control chamber. The duration of thetoasting cycle and, therefore, the resultant degree or "color" to whichthe toast is toasted, is adjusted by a toast color control cam thatmoves the switch contacts nearer to or farther from the end of thebimetal-driven switch operating shaft, so that the excursion of theshaft from the beginning of a toasting cycle to the end of a toastingcycle required to close the solenoid switch can be changed to obtaindifferent toast colors.

Notwithstanding the several elements that comprise a household toaster,household toasters are usually remarkably inexpensive. The low costpartly results from the use of sophisticated manufacturing andassembling techniques. There is however, an ever-present need to reducethe costs of toasters in order to provide toasters to the public at lowcosts and meet the demands of a competitive industry.

SUMMARY OF THE INVENTION

An object of this invention is to provide an improved household electrictoaster. More particularly, an object of this invention is to provide arugged, high quality household toaster which can be manufactured atrelatively low cost. To accomplish these objects, this inventionutilizes improvements in the following areas of toaster construction andoperation:

1. The toaster has a metal body and plastic end panels. The end panelshave cooling inlet vents near their lower ends that admit ambient airinto the ends of the toaster. The flowing air flows outwardly throughair outlet vents in the top wall of the metal body. The cooling issufficient to enable the use of an inexpensive plastic material,preferably polypropylene, for molding the end panels. In contrast,plastic end panels are normally made from plastic materials that have agreater heat rating.

2. Each bread lifter is made entirely from a wire rod and is connectedto the lifter plate without the use of fasteners, welding or solderingand, for ease of assembly, in a manner that prevents rotation of thelifter about a vertical axis.

3. The bread lifter extension is made entirely from a wire rod.

4. A toast color cam is made entirely from a single piece of sheet metaland is supported by the front frame plate of the toaster.

Other objects and advantages of this invention will become apparent inview of the following description taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a fragmentary perspective view of a toaster in accordance withthis invention.

FIG. 2 is an exploded, perspective view of parts of the toaster of FIG.1.

FIG. 3 is an exploded perspective view of the frame and toastermechanical operating parts shown assembled in FIG. 2.

FIG. 4 is a highly simplified, diagrammatic and cross-sectional view ofthe toaster of FIG. 1, and illustrates the path of ambient air flowingupwardly inside the ends of the toaster.

FIG. 5 is a perspective view of a bread lifter assembly shown also inFIGS. 1 and 2.

FIG. 6 is an elevational view of the bread lifter assembly of FIG. 5.

FIG. 7 is a fragmentary, plan view of a portion of the front of thetoaster showing a toast color control assembly including a one-piecetoast color control cam in accordance with this invention.

FIG. 8 is view similar to FIG. 7 but with the toast color control cam ina different position of adjustment.

FIG. 9 is a front elevational view of the control chamber of the toasterof FIG. 1.

FIG. 10 is fragmentary, partly cross-sectional and partly plan viewtaken on line 10--10 of FIG. 9 of a portion of the toast color controlassembly illustrating a carriage plate hooked by a latch plate orarmature.

FIG. 11 is a view similar to FIG. 10 but showing the latch plate movedaway from the carriage plate by the lifter extension.

DETAILED DESCRIPTION

With reference first to FIGS. 1 and 2, this invention is shown embodiedin a household electric toaster 20 comprising a frame 22 and operatingparts to be described below partly covered by a tubular metal body 24having its opposite ends closed by plastic end panels, namely a frontend panel 26 and a rear end panel 28. The end panels 26 and 28 areconnected to the metal body 24 by means of metal clips 30 on the endpanels 26 and 28 that extend into cooperating apertures 32 in the upperends of the metal body 24. The end panels 26 and 28 are also connectedto the metal body 24 by screws (not shown) that extend upwardly throughscrew-receiving apertures 34 in the bottom portions of the metal body 24and into holes 36 in mounting flanges 38 adjacent the bottom edges ofthe end panels 26 and 28. (only the holes 36 and the mounting flange 38of the rear end panel 28 are illustrated in the drawings. These partsare essentially identical to the corresponding parts of the front endpanel 26.) With reference also to FIGS. 3 and 4, the toaster frame 22includes a base frame plate 40, a top frame plate 42, a front frameplate 44 and a rear frame plate 46. The front frame plate 44 separatesthe toaster 20 into a control chamber 48 at its forward end and atoasting chamber 50. Toasting chamber 50 is heated by plural heatingelements 52 that extend substantially the length thereof. The rear frameplate 46 separates the toasting chamber 50 from a rear chamber 54. Largeopenings 55 in the top wall of the metal body 24 open to the toastingchamber 50 enable bread or other food items to be toasted to be placedin and removed from the toasting chamber 50.

FIG. 3 also shows wire grills 56, a power switch assembly 58, and acrumb tray 60, all of which are conventional and form no part of theinstant invention.

In order to use inexpensive plastic materials which do not have a highheat rating, a front heat shield 62 is located in the control chamber 48and a rear heat shield 64 is located in the rear chamber 54. The heatshields 62 and 64 preferably are integrally formed with and depend fromthe top frame plate 42. Furthermore, the front end panel 26 has severalinlet cooling vents 66 in the lower portion thereof that admit ambientair into the control chamber 48. Similarly, the rear end panel 28 hasseveral cooling vents 68 in the lower portion thereof that admit ambientair into the rear control chamber 54. Ambient air will also enter thecontrol chamber 48 and the rear chamber 54 through various openings inthe base frame plate 40.

Referring to FIG. 4, the ambient air entering the control and rearchambers 48 and 54 flows upwardly therethrough and outwardly through twopairs of air outlet vents 70 and 72 in the top wall of the metal body 24which overlie and open to, respectively, the control chamber 48 and therear chamber 54. Provision of the heat shields 62 and 64 and the ventingof ambient air through the control chamber 48 and the rear chamber 54,inexpensive plastic materials can be used to mold the end panels 26 and28. End panels 26 and 28 made from polypropylene are presently preferredbecause polypropylene is relatively inexpensive and easy to use.

With reference to FIGS. 3, 5, 6 and 9, a bread lifter assembly,generally designated 80 is mounted for vertical movement on a guide post82 that extends vertically between the base frame plate 40 and the topframe plate 42. The lifter assembly includes a generally vertical breadlifter carriage plate 84 formed from sheet metal and adapted to besupported for vertical movement in the control chamber 48. The carriageplate 84 has a top margin 86, a bottom margin 88, and opposite sidemargins 90. A pair of angled slots 92 open to respective ones of theside margins 90 and an L-shaped tab 96 extends forwardly and upwardlyfrom the front face of the sheet material forming the carriage plate 84,the tab being struck out of the sheet material.

The lifter assembly 80 further includes a pair of bread lifters 98 forholding food items to be toasted in the toasting chamber. Each breadlifter comprises a one-piece wire rod having a first,generally-horizontal, food-supporting section or arm 100 in which thewire rod extends along a zig-zag or tortuous path having excursionsextended to both sides beyond a horizontal center axis of the path toprovide an upwardly-facing, food-supporting surface 102. Each breadlifter has a second, generally-vertical, connecting section 104extending upwardly from an end of the first section 100, the secondsection 104 having a lower end portion 106 extending along the rear faceof the carriage plate 84, a horizontal slot section 108 extendingthrough one of the angled slots 92, and an intermediate section 110extending along the front face of the carriage plate 84, and an upperend portion 112 extending at approximately 900 to the intermediatesection 110 and confined between the L-shaped tab 96 and the front faceof the carriage plate 84. This construction enables one to easily insertthe bread lifters 98, after they are previously connected to the breadcarriage plate 84 as illustrated, through slots 114 in the front frameplate 44 (FIGS. 3 and 9). Note that the bread lifters 98 woulduncontrollably pivot about their horizontal slots section 108 if theupper end portion 112 was not confined by the L-shaped tab 96 and thefront face of the carriage plate 84. Small tabs 116 struck out from thecarriage plate 84 assist in holding the bread lifters 98 in a horizontalorientation until the bread lifters 98 are inserted into the toastingchamber 50. After assembly into the toasting chamber 50, the breadlifters 98 are confined to their horizontal orientations by verticalslots 118 and 120 in the front and rear frame plates 44 and 46,respectively.

With reference to FIGS. 5, 6 and 9 through 11, the bread lifter assembly80 further includes a bearing 130 at its right side lower corner marginadapted to be hooked by a pivotally-mounted latch plate or armature 132that holds said lifter carriage plate 84 in its lower, toasting positionduring a toasting cycle. In accordance with this invention, the carriageplate 84 further has a pair of forwardly-extending support plates 134adjacent its upper margin struck out of the sheet material that formssaid lifter plate 84. The support plates 134 have upper surfacescontoured to pivotally support a lifter extension, generally designated136 which is also made from a one-piece wire rod. The lifter extension136 has a horizontal, transversely-extending section 138 supported bysaid support plates 134 for pivotal movement about the major axis of thetransversely-extending section 138, and a vertical section 140 dependingfrom the outer, side end of the transversely-extending horizontalsection for engaging said latch and moving said latch out of engagementwith the bearing 130 upon pivotal movement of the lifter extension 136.

The lifter extension 136 further includes a horizontal,forwardly-extending front end portion 142 adapted to receive a lifterknob 144 (FIGS. 1 and 2) for lowering the lifter assembly 80 and fordisengaging the latch plate 132 from the lifter plate 84 by pivotalmovement of the lifter extension 136 about the horizontal axis of itstransversely-extending section 138.

In normal operation of the toaster 20, a solenoid coil 146 is energizedat the end of toasting cycle and draws the latch plate or armature awayfrom the bearing 130. This releases the bread lifter assembly 80whereupon it moves upwardly under the bias of a lifter spring 148 (FIGS.3 and 9). A toasting cycle can be interrupted by raising the lifter knob144 whereupon a horizontal arm 150 at the bottom of the vertical section140 of the lifter extension pushes the latch plate 132 away from thebearing 130 as illustrated in FIGS. 10 and 11.

Referring now to FIGS. 3, 7 and 8, normal operation of the toaster iscontrolled by a bimetal assembly 152 that drives a switch operatingshaft 154 outwardly as the temperature within the toasting chamberincreases. Switch contacts (not shown) within a switch housing 156 arecaused to close when the operating shaft pushes one contact intoengagement with the other. Closure of the switch causes the solenoidcoil to be energized and pull the latch 132 away from the bearing 130whereupon the bread carriage is released and moves upwardly to open thepower switch assembly 58 to terminate the toasting cycle. The spacingbetween the switch contacts and the near end of the operating shaft whenthe toaster is cold determines the excursion of the switch operatingshaft 154 necessary to complete closure of the switch contacts. Inaccordance with this invention, the end of the switch housing 156carrying the switch contacts for the solenoid coil 146 is pivotedagainst the bias of a switch-housing spring 158 by a color control cam160 made from a single piece of sheet metal that extends through a slot162 in the front plate 44 from which it derives support.

Having thus described our invention, we claim:
 1. A bread lifterassembly for a toaster having a toasting chamber and a control chamber,comprising:A. a generally vertical bread lifter carriage plate formedfrom sheet material and adapted to be supported for vertical movement inthe control chamber, said plate having:i. a top margin, a bottom margin,and opposite side margins extending between the opposite ends of saidtop margin and said bottom margin; ii. a slot opening to one of saidside margins; and iii. an L-shaped tab extending forwardly and upwardlyfrom the front face of the sheet material forming said plate; B. a breadlifter for holding food items to be toasted in the toasting chambercomprising a one-piece wire rod having:i. a first, generally-horizontal,food-supporting section in which said wire rod extends along a tortuouspath having excursions extended to both sides beyond a horizontal centeraxis of said path to provide an upwardly-facing, food-supportingsurface; and ii. a second, generally-vertical, connecting sectionextending upwardly from an end of said first section, said secondsection having a lower end portion extending along the rear face of saidcarriage plate, a transient section extending through said slot, anintermediate section extending along the front face of said plate, anupper end portion extending at approximately 90° to said intermediatesection and confined between said tab and the front face of saidcarriage plate.
 2. The bread lifter assembly of claim 1 wherein:A. saidlifter plate further includes:i. an upwardly-facing bearing surfaceadjacent its lower margin adapted to be hooked by a latch that holdssaid lifter plate in its lower, toasting position during a toastingcycle, and ii. a pair of forwardly-extending support plates adjacent itssaid upper margin struck out of the sheet material that forms saidlifter plate, said support plates having upper margins contoured tosupport a wire rod in a horizontal path extending across the front faceof said lifter plate; and B. said lifter assembly further includes alifter extension made from a one-piece wire rod including:i. ahorizontal, transversely-extending section mounted on said lifter platefor pivotal movement about the major axis of said transversely-extendingsection, and ii. a vertical section depending from one end of saidhorizontal section for engaging said latch and moving said latch out ofengagement with said bearing surface upon pivotal movement of saidlifter extension.
 3. The lifter assembly of claim 2 wherein said lifterextension further includes a horizontal, forwardly-extending end portionadapted to receive a lifter knob for lowering the lifter assembly in thetoaster and for disengaging the latch from said lifter plate by pivotalmovement of said lifter extension.
 4. A bread lifter assembly for atoaster having a toasting chamber and a control chamber, comprising:A. agenerally vertical bread lifter carriage plate formed from sheetmaterial and adapted to be supported for vertical movement in thecontrol chamber, said plate having:i. an upwardly-facing bearing surfaceat its lower margin adapted to be hooked by a latch that holds saidlifter plate in its lower, toasting position during a toasting cycle,and ii. a pair of forwardly-extending support plates adjacent its saidupper margin struck out of the sheet material that forms said lifterplate; and B. a lifter extension made from a one-piece wire rodincluding:i. a horizontal, transversely-extending section mounted onsaid lifter plate for pivotal movement about the major axis of saidtransversely-extending section, and ii. a vertical section dependingfrom one end of said horizontal section for engaging said latch andmoving said latch out of engagement with said bearing surface uponpivotal movement of said lifter extension.
 5. The lifter assembly ofclaim 4 wherein said lifter extension further includes a horizontal,forwardly-extending end portion adapted to receive a lifter knob forlowering the lifter assembly in the toaster and for disengaging thelatch from said lifter plate by pivotal movement of said lifterextension.